The "User Agent Accessibility Guidelines 1.0" (UAAG 1.0)
is part of a set of accessibility guidelines published by the Web Accessibility
Initiative (WAI) of the World Wide Web Consortium. The WAI
Guidelines were designed to present a consistent model for Web accessibility in
which responsibilities for addressing the needs of users with disabilities are
shared (and distributed among) authors, software developers, and specification
writers.

The "User Agent Accessibility Guidelines 1.0" explains what software
developers can do to improve the accessibility of mainstream browsers and
multimedia players so that people with visual, hearing, physical, cognitive,
and neurological disabilities will have improved access to the World Wide Web.
A user agent that conforms to these guidelines will
enable access through its own user interface and through other internal
facilities, including its ability to communicate with other technologies
(especially assistive technologies). UAAG 1.0 is not aimed at developers of
assistive technologies (e.g., screen magnifiers, screen readers, speech
recognition software, alternative keyboards, braille devices, etc.), although
these technologies will be essential to ensuring Web access for some users with
disabilities.

UAAG 1.0 is developed by the W3C User Agent Accessibility Guidelines Working
Group (UAWG), whose participants include software
developers, users with disabilities, and international experts in the field of
accessibility technologies.

"Authoring Tool Accessibility Guidelines 1.0" [ATAG10], which explains to
developers how to design authoring tools that are accessible to authors with
disabilities, and that produce accessible Web content (i.e., content that
conforms to WCAG 1.0).

"XML Accessibility Guidelines 1.0" [XAG10], which explains to
developers how to design accessible formats and applications using
XML.

The following scenarios show how some of the requirements "User Agent
Accessibility Guidelines 1.0" benefit users with disabilities. These and
similar scenarios, as well as information about assistive technologies and
different types of disabilities, are described in "How People with Disabilities
Use the Web" [PWD-USE-WEB].

Note: UAAG 1.0 does not address all accessibility needs;
the other WAI Guidelines include complementary requirements for authors,
authoring tool developers, and specification designers.

Mr. Jones, a reporter for an on-line journal, makes extensive use of the Web
to conduct research and to publish articles. Over his twenty-year career, he
has developed repetitive stress injury (RSI) in his hands
and arms, and it has become painful for him to type. He uses a combination of
voice recognition and an alternative keyboard to prepare his articles, but he
doesn't use a mouse. One of the requirements of UAAG 1.0 is
that a conforming user agent be fully operable through the keyboard and
implement conventional keyboard programming interfaces
(APIs). Since many alternative input devices make use of
conventional keyboard APIs, this allows Mr. Jones to use an alternative
keyboard.

Ms. Martinez is taking several distance learning courses in physics. She is
deaf. She had little trouble with the curriculum until the university upgraded
their on-line courses to a multimedia approach, using an extensive collection
of audio lectures. While the audio benefitted users with blindness and
low-vision, and users with reading disabilities, Ms. Martinez required the
information in alternative formats. To make the classes more accessible, the
university provided text transcripts in addition to the audio versions of the
lectures. The university also provided text captions (using
SMIL) synchronized with the audio and video of some of the
lectures. One of the requirements of UAAG 1.0 is that a
conforming user agent display captions and other "conditional content" that
authors may have provided to improve accessibility but that is not rendered by
default.

Ms. Laitinen is an accountant at an insurance company that uses Web-based
formats over a corporate intranet. She is blind. She uses a screen reader in
conjunction with a graphical desktop browser and a speech synthesizer. She uses
speech output, combined with navigation of the important links on a page, to
scan documents rapidly for important information, and has become accustomed to
listening to speech output at a speed that her co-workers cannot understand at
all.

For Ms. Laitinen it is critical that her desktop browser communicate with
available assistive technologies (screen reader, speech synthesizer).
UAAG 1.0 includes requirements related to communication
(through APIs) and to the implementation of system
conventions (which increase the likelihood of interoperability). Communication
with her assistive technology does not suffice to make her browser more
accessible, however. Some of her other needs that are addressed by
UAAG 1.0 include:

the ability to operate it through the keyboard (since a mouse is almost
useless to her);

the ability to move focus to links and form controls (so that her assistive
technologies know "where she is looking");

access to descriptions of images and video (since these text descriptions
can be read by her speech synthesizer);

The twelve guidelines in this document state general principles for the
development of accessible user agents. For instance, guideline 1 reads:

Guideline 1: Support input and output device-independence
Ensure that the user can interact with the user agent (and the content it
renders) through different input and output devices.

Each guideline regroups a related list of "checkpoints". The checkpoints are
the heart of UAAG 1.0, because they make the requirements on
which conformance is based. There are just over eighty "checkpoints", ranked
according to their importance to accessibility (priority 1 for most important,
then priority 2 and 3).

Here is one example of a checkpoint:

1.1 Full keyboard access
(P1)

Ensure that the user can operate, through keyboard input
alone, any user agent functionality available through the user
interface.

Because people with disabilities may not be able to use certain input (e.g.,
pointing device) or output modes (e.g., visual, audio), the user agent must be
operable through a number of different input and output modes. Keyboard input
and text output enable device-independence in today's operating environments,
so UAAG 1.0 emphasizes support for these modes.

A checkpoint may include more than one requirement, and may also include
informative Notes that give examples or further explanation. Guideline 1
includes three checkpoints, including checkpoint 1.1.

Please note that the requirements of UAAG 1.0 are the checkpoints,
not the guidelines.

A user agent may satisfy the requirements of UAAG 1.0 in many different
ways. The checkpoints of UAAG 1.0 have therefore been
written to be independent of specific markup languages (e.g., the Hypertext
Markup Language (HTML) or Scalable Vector Graphics
(SVG)) and operating systems. To assist developers in
understanding how to satisfy the requirements for specific technologies and
operating systems, the User Agent Accessibility Guidelines Working Group has
published a separate document entitled "Techniques for User Agent Accessibility
Guidelines 1.0" [UAAG10-TECHS]. The
Techniques document includes references to other accessibility resources (such
as platform-specific software accessibility guidelines), examples, and
suggestions for approaches that may be part of satisfying the requirements of
UAAG 1.0.

Conformance to UAAG 1.0 means that a user agent has
satisfied a set of the document's requirements. Conformance is expected to be a
strong indicator (but not a guarantee) of the accessibility of a user
agent.

The conformance model of UAAG 1.0 has been designed to
allow different types of user agents with different input and output
capabilities to conform. At the same time, the model is designed so that:

people reading claims can determine whether a conforming user agent is
likely to meet their accessibility needs, and

people can compare claims about different user agents with relative
ease.

For instance, user agents with the following capabilities might both
conform:

one user agent supports several audio, image, and video formats, and
keyboard input.

another user agent does not support video output, but supports synthesized
speech output instead, and is entirely operable through keyboard and voice
input.

UAAG 1.0 includes requirements for conformance
claims, e.g., version information about the software components that
together satisfy the checkpoints, information about the platforms on which they
run, information about which markup languages are implemented as part of
conformance, which requirements the user agent does not satisfy, and more.

We encourage developers to use the checklist
[UAAG10-CHECKLIST]
appendix to UAAG 1.0 as a tool for evaluating user agents
for conformance.